JP3047317U - Brushless motor and video cassette recorder - Google Patents

Abstract

(57) [Summary] [Problem] To always extract an FG signal correctly and to prevent noise from occurring in an image. SOLUTION: In this brushless motor 1, an FG detecting member 5 is provided on a metal circuit board 4 and a motor section is fixed. Then, at least one side of the end portion of the circuit board 4 is bent into an L-shape in such a manner that a side parallel or substantially parallel to a line connecting a portion where a force is applied to the circuit board 4 and a portion where the motor portion is fixed is bent. 7 is assumed. This motor 1
Is attached to, for example, a video cassette recorder. At this time, the brushless motor 1 is fixed to the deck 2 of the main body, and the connector 6 attached to the circuit board 4 of the brushless motor 1 is engaged with the engaged member 37 provided on the main board 36 of the main body.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a brushless motor such as a capstan motor for a video cassette recorder (hereinafter referred to as “VCR”) having an FG detecting member for detecting a rotation frequency signal, and a VCR incorporating the motor.

[0002]

[Prior art]

 2. Description of the Related Art A brushless motor 21 has been known as a capstan motor for rotating a VCR capstan shaft, as described in Japanese Patent Application Laid-Open No. HEI 8-109931. As shown in FIG. 6, the brushless motor 21 mainly includes a stator 24 and a circuit board 25 fixed to a bearing holder 23, a rotating shaft 26, and a rotor 27 fixed to one end of the rotating shaft 26. ing.

[0003] Such a brushless motor 21 is required to rotate at a high speed because of a feature of use such as driving a capstan shaft of a VCR, and also needs to keep an accurate rotation speed constant. . Therefore, a high-performance magneto-sensitive element for accurately detecting a rotation frequency signal (hereinafter referred to as an FG signal) output from a rotation frequency generating magnet (hereinafter referred to as an FG magnet) M attached to the rotor 27, for example, FG It has a configuration in which the detection head 28 is fixed to a substrate or the like.

As shown in FIG. 7, the FG magnet M is, for example, a circular magnet fixed to the outer peripheral portion of a rotor 27 formed in a circular shape. N poles and S poles are alternately magnetized at a pitch of about 5 mm, and are formed by 720 poles. The brushless motor 21 has two modes, an EP mode (triple mode) and an SP mode (standard mode), and the rotation speed of the rotor 27 changes according to these modes. The FG magnet M can support both the EP mode (triple mode) and the SP mode (standard mode), that is, no wow and flutter occur when the rotor 27 is rotating in either mode. The number of magnetizations is as follows.

[0005] The bearing holder 23 has a cylindrical portion 23a having a space for rotatably inserting the rotary shaft 26 therein, and a flange portion formed to project radially outward from one end side of the cylindrical portion 23a. 23b. Metal bearings 29, 29 are fixed inside the cylindrical portion 23a, and the rotating shaft 26 is supported by the metal bearings 29, 29 at two points. The cylindrical portion 23a is provided with a window 23c for allowing a pinch roller R provided as another component for driving the tape to slidably contact the rotary shaft 26 from outside.

[0006] A stator core 31 around which the coil 30 is wound is fixed outside the flange portion 23b, and the coil 30 and the stator core 31 constitute the stator 24. Further, a plurality of screw holes 23d are formed in the flange 23b as shown in FIG. The screw holes 23d are used to fix the stator core 31 and the circuit board 25 to the bearing holder 23 with screws 32, or to fix the brushless motor 21 itself to the VCR deck 22 shown by a dashed line in FIG. .

On the other hand, near the one end of the rotating shaft 26, a cup-shaped rotor 27 that covers the stator 24 from one side is inserted and fixed. Further, a pulley 33 for using the driving force of the brushless motor 21 to other members via a belt (not shown) is fixed to the outer side in the axial direction of the rotating shaft 26, that is, to the tip portion. A rotor magnet 34 is fixed to a radially outer end portion of the rotor 27 so as to face the stator core 31 of the stator 24. When a current flows through the coil 30 of the stator 24 to magnetize the stator core 31, the rotor magnet 34 is repelled or attracted to the stator core 31 and rotates. As a result, the rotor 27 rotates around the rotation shaft 26 as a rotation center.

The circuit board 25 has a predetermined circuit pattern printed directly on a flat metal member, or is fixed to a bearing holder 23 using a metal member as a base, and the base is formed of a resin member. A material obtained by bonding and fixing members is used. The circuit board 25 is fixed to the bearing holder 23 so that a part thereof protrudes radially outward from outer peripheral ends of the stator 24 and the rotor 27. An FG detection head 28 as a magnetic sensing element for detecting an FG signal generated from the FG magnet M when the rotor 27 rotates and a connector 35 are fixed to the protruding portion of the circuit board 25. The brushless motor 21 processes an FG signal detected by the FG detecting head 28 in a control circuit described later and uses the processed signal for rotation control of the rotor 27.

The connector 35 is engaged with an engaged member 37 provided on a main board 36 of the VCR, and electrically connects a control circuit of the VCR and the brushless motor 21. As a result, the rotation of the brushless motor 21 is controlled by the control circuit.

[0010]

[Problems to be solved by the invention]

 However, when the conventional brushless motor described above is attached to the VCR, that is, when the connector 35 of the brushless motor 21 fixed to the deck 22 is engaged with the engaged portion 35 of the main board 36, the circuit board 25 A phenomenon occurs in which the positional relationship between the FG detecting member 28 and the FG magnet M changes. If the positional relationship between the FG magnet M and the FG detecting member 28 changes, the FG signal is not detected by the FG detecting member 28 or becomes a weak signal, and the precision of the rotation control of the motor decreases. Then, the tape feed of the VCR becomes unstable, resulting in noise or the like in the obtained image.

It is an object of the present invention to provide a brushless motor capable of always correctly extracting an FG signal, and to provide a video cassette recorder which does not generate noise or the like in an image.

[0012]

Means for Solving the Problems In order to achieve the above object, the present invention provides a brushless motor in which an FG detecting member is provided on a metal circuit board and a motor section is fixed. At least one side of the end, which is parallel or substantially parallel to a line connecting a portion where a force is applied to the circuit board and a portion where the motor portion is fixed, is bent into an L-shape. According to a second aspect of the present invention, in the brushless motor according to the first aspect, one side bent into an L shape is one side near a connector provided on a circuit board.

According to a third aspect of the present invention, in the brushless motor according to the first or second aspect, one side bent into an L shape is one side near an FG detecting member provided on a circuit board. Further, according to a fourth aspect of the present invention, in the brushless motor according to the first, second or third aspect, the circuit board is configured by laminating and fixing a board member made of a material other than the metal member to a base metal member. The metal member is bent toward the substrate member.

According to a fifth aspect of the present invention, in the brushless motor according to the first, second, third or fourth aspect, a line connecting a portion where the motor portion is fixed and a portion where the connector is provided is provided. The side end is a long side of a straight line, and the long side is a side bent into an L shape. In addition, according to the invention of claim 6, in the brushless motor according to any one of claims 1 to 5, the height of the bent portion is set to 1 to 2 mm.

Further, a video cassette recorder according to a seventh aspect of the present invention includes the brushless motor according to any one of the first to sixth aspects fixed to a deck of the main body, and a connector attached to a circuit board of the brushless motor. It is engaged with the engaged member provided on the main board.

The brushless motor according to the present invention is a motor having an FG detecting member, such as a capstan motor used for driving a capstan of a VCR. In the case of a VCR, the capstan motor is fixed to the deck of the VCR, and the connector is engaged with the deck together with the main board of the VCR. At the time of the engagement, a force is applied from the main board side, and the circuit board of the capstan motor tends to bend. If it bends, the positional relationship of the FG detecting member on the circuit board will be deviated, and adverse effects will occur such that the FG signal is not detected.

In the present invention, at least one side of the end of the circuit board, which is parallel or substantially parallel to a line connecting a portion where a force is applied to the circuit board and a portion to which the motor is fixed, is bent into an L shape. Therefore, the circuit board does not bend even when the above-described engagement is performed. Therefore, the FG signal can always be taken out correctly. When such a brushless motor is incorporated in a VCR, a VCR that does not cause noise or the like in an image and that can obtain a high-quality and stable image is obtained.

[0018]

[Embodiment of the invention]

 An embodiment of the brushless motor of the present invention and a video cassette recorder incorporating the brushless motor will be described with reference to FIGS.

The overall configuration of the brushless motor 1 according to the present embodiment is substantially the same as that of the brushless motor 21 described in the related art. Therefore, in the present embodiment, the description of the same configuration as that of the prior art shown in FIG. 6 will be omitted or simplified, and the same members will be described using the same reference numerals. Further, in the present embodiment, only the circuit board 4 and its peripheral structure are different from each other, so that the description will be given mainly of the portions.

The brushless motor 1 is fixed to a deck 2 of a VCR by screws 3. On the other hand, on a circuit board 4 of the brushless motor 1, an FG detecting head 5 serving as an FG detecting member, a connector 6, and other circuit components (not shown) are mounted. The circuit board 4 is obtained by directly printing a predetermined circuit pattern on a flat metal member made of iron, and one side a of the end is a surface on which the FG detection head 5 and the like are provided. The bent portion 7 is formed by being bent into an L-shape in the opposite direction.

When the deck 2 is attached to the main board 36 of the VCR, the connector 6 of the brushless motor 1 fixed to the deck 2 engages with the engaged member 37 of the main board 36. At this time, the circuit board 4 receives a force from the main board 36 and tries to bend in the direction of arrow A in FIG. However, in this embodiment, the end a of the long side along the connector 6 from the bearing holder 23 is bent into an L shape, and the bent portion 7 is formed, so that the circuit board 4 does not bend. For this reason, it is possible to avoid a situation where the circuit board 4 is attached in a bent state.

In this embodiment, since the bent portion 7 is bent to the opposite side to the rotor 27, it is preferable when the distance between the rotor 27 and the circuit board 4 is small. Further, since the FG detection head 5 is provided such that the line connecting the head 15 and the center of the bearing holder 23 is parallel to the bent portion 7, the FG detection head 5 is provided at the least bent portion. It will be attached.

As described above, by bending the long side, which is substantially parallel to the line connecting the center of the bearing holder 23 and the connector 5 and equal to or longer than the distance connecting them, into an L-shape, the force received by the connector 6 Is strong, the circuit board 4 does not bend, which is preferable. When the FG detecting head 5 is installed so that the line connecting the FG detecting head 5 and the bearing holder 23 is parallel to the bent portion 7, the influence of the bending becomes the least, which is more preferable.

The height H of the bent portion 7 is preferably 0.5 to 3 mm, and most preferably 1 to 2 mm, in consideration of the prevention force of the bending and the distance to other members. That is, when the height H is reduced, the height H can be inserted into the gap between the deck 2 and the circuit board 4 or between the circuit board 4 and the rotor 27. On the other hand, when the height H is increased, the deflection prevention force is increased. Therefore, in order to sufficiently achieve both of these objects, the thickness is preferably about 0.5 to 3 mm, and most preferably 1 to 2 mm.

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications may be made without departing from the scope of the present invention. It is possible. For example, in the above-described embodiment, the bent portion 7 is formed by bending to the deck 2 side of the VCR, but may be bent to the rotor 27 side (= main substrate 36 side) as shown in FIG.

As shown in FIG. 5, the circuit board 4 is formed by laminating and fixing a resin substrate member 4 b on an iron metal member 4 a serving as a base, and the bent portion 7 of the metal member 4 a The height may be the same as the thickness of the member 4b. In this case, it is preferable that the front end surface of the bent portion 7 and the upper surface of the substrate member 4b be flush with each other, but the front end surface of the bent portion 7 may be slightly protruded, or conversely, may be lowered. Further, as shown in FIG. 5, it is preferable that the substrate member 4b abuts against the side surface of the bent portion 7, but a gap may be provided between the base member 4b and the bent portion 7 without abutting. Further, the bent portion 7 of the metal member 4a may be formed by bending to the opposite side instead of the substrate member 4b side.

Further, although the circuit board 4 of the embodiment of FIGS. 1 to 4 and the metal member 4a of FIG. 5 are made of iron, other metal members may be used.

Further, in the above description, the case where the brushless motor 1 is attached to the VCR has been described, but the present invention can also be applied to the case where it is attached to another device such as a tape recorder or a video camera. Further, the present invention can be applied to other brushless motors other than the capstan motor as long as the brushless motor is provided with the FG detecting member. In addition, other detecting means such as an MR sensor can be employed as the FG detecting member in addition to the FG detecting head 5.

The present invention can also be applied to a connector having no connector 6. That is, when the circuit connection is made by other means instead of the connector 6, the formation of the bent portion 7 increases the steeliness of the circuit board 4, and gives a slightly strong force to a predetermined portion of the circuit board 4 during assembly. Even if the FG detecting member 5 does not bend, the position accuracy of the FG detecting member 5 can be maintained high.

Further, the bent portion 7 is an end portion of at least one side of the circuit board 4 and a portion where a force is applied to the circuit board when the motor is mounted and a portion where the motor portion is fixed (= bearing holder 23 portion). The end portion a may be used as long as it is parallel or substantially parallel to the line connecting. For example, as shown in FIG. 2, the end b or the end c may be used. However, end d and end e which do not correspond to this configuration are not preferable. Further, it is preferable that the bent portion 7 extends over one end portion. However, the bent portion 7 may be formed halfway, only at the center portion, or at both sides without bending at the center.

[0031]

[Effect of the invention]

 In the brushless motor according to the first aspect, even when a force is applied to the circuit board when the motor is mounted, the circuit board does not bend, and the positional relationship of the FG detecting member is correctly maintained. Therefore, the rotation of the motor is controlled correctly, and stable rotation can be obtained.

Further, in the invention according to the second aspect, since one side near the connector is bent, even when a force is applied to the connector when the connector is used to connect to another circuit, the circuit board is slack. I don't know. In addition, in the invention according to claim 3, since one side near the FG detecting member is bent, the influence of the bending on the FG detecting member is reduced.

In the invention according to the fourth aspect, the metal member constituting the circuit board is bent toward the board member, which is advantageous in terms of space. Further, in the invention according to claim 5, since the long side of the side of the connector is bent, the bending prevention force is increased, and the influence on the FG detecting member can be further reduced. In addition, since the height of the bent portion is set to 1 to 2 mm in the invention according to the sixth aspect, it is preferable in terms of both the space and the deflection preventing surface.

In the video cassette recorder according to the seventh aspect, when assembling the deck and the main board, the assembly can be performed quickly and efficiently without considering the bending of the circuit board of the brushless motor, and the productivity is improved. In addition, since the position accuracy of the FG detecting member can be maintained at a high level, noise and the like do not occur in an image, and stable recording and reproduction can be performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a brushless motor according to an embodiment of the present invention.

FIG. 2 shows the brushless motor shown in FIG.
It is the principal part top view seen from the I direction.

FIG. 3 is a side view of a main part as viewed from a direction indicated by an arrow III in FIG. 2;

FIG. 4 is a side view of a main part showing another example of a circuit board portion of the brushless motor shown in FIG. 1;

FIG. 5 is a side view of a main part showing a modification of the circuit board of the brushless motor shown in FIG. 1;

FIG. 6 is a longitudinal sectional view showing the entire configuration of a conventional brushless motor.

7 is a perspective view showing a part of the FG magnet of the brushless motor shown in FIG.

FIG. 8 is an exploded perspective view showing a bearing holder and a metal bearing of the brushless motor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Deck 4 Circuit board 5 FG detection head (FG detection member) 6 Connector 7 Bend (L-shaped part)

Claims (7)

[Utility model registration claims] 1. A brushless motor in which an FG detecting member is provided on a metal circuit board and a motor section is fixed, wherein at least one side of an end of the circuit board, a portion where a force is applied to the circuit board, and The side parallel or substantially parallel to the line connecting the portion where the motor section is fixed is L
A brushless motor characterized by being bent into a mold. 2. The brushless motor according to claim 1, wherein one side bent into the L shape is one side near a connector provided on the circuit board. 3. The brushless motor according to claim 1, wherein one side bent into the L shape is one side near an FG detecting member provided on the circuit board. 4. The circuit board according to claim 1, wherein a substrate member made of a material other than the metal member is laminated and fixed to a metal member serving as a base, and the metal member is bent toward the substrate member. Item 4. The brushless motor according to item 1, 2 or 3. 5. A side end of a line connecting a portion where the motor portion is fixed and a portion where a connector is provided is a long side of a straight line, and the long side is a side bent into the L-shape. The brushless motor according to claim 1, 2, 3, or 4, wherein 6. The brushless motor according to claim 1, wherein a height of the bent portion is set to 1 to 2 mm. 7. An engaged member, wherein the brushless motor according to claim 1 is fixed to a deck of a main body, and a connector attached to the circuit board of the brushless motor is provided on a main board of the main body. A video cassette recorder characterized by being engaged with a video cassette recorder.